Web tension regulating mechanism for hydraulic rewinders



Sept. 11, 1962 P. ZERNOV ETAL 3,053,468

WEB TENSION REGULATING MECHANISM F OR HYDRAULIC REWINDERS Filed July 21, 1960 3 Sheets-Sheet 1 ?ETER ZERNOV GUNTHER H.MAHN

ATTORNEYS.

F I 1N VEN TORS Sept- 1 1962 P. ZERNOV ETAL WEB TENSION REGULATING MECHANISM FOR HYDRAULIC REWINDERS Filed July 21, 1960 3 Sheets-Sheet 2 ml lE' a W mun.

F l G 4 INVENTORS ,RETER ZERNOV BY GUNTHERH.MAHN

ATTORNEYS.

United States Patent Ofific e 3,053,468 Patented Sept. 11, 1962 3 053,468 WEB TENSION REGULATING MECHANISM FOR HYDRAULIC REWINDERS Peter Zernov and Giinther H. Mahn, Milwaukee, Wis.,

assignors, by mesne assignments, to Miehle-Goss- Dexter, Incorporated, Chicago, 11]., a corporation of Delaware Filed July 21, 1960, Ser. No. 44,345 Claims. (Cl. 242-75.53)

This invention relates to hydraulic rewinders for web material.

Rewinders of the type to which this invention relates are adapted to form huge rolls that are several feet in diameter, are several feet long and weigh several tons. It is particularly important that these rolls be formed so the core or the inner wraps Will. not slip during winding of the web thereon, and thereby cause the roll to walk out.

This walk on is an axial shifting of either the core relative to the rest of the roll, or the inner wraps of the roll relative to the rest of the roll. It is caused in certain types of board by the application of a constant tension on the web during roll formation because the inner wraps were wound with the tension acting through a relatively small moment arm and as the roll grows in diameter, this moment arm increases and if the same Web tension is used, the force acting on the inner Wraps is much greater at a later stage of roll formation. At tempting to later transmit this greater force through these earlier wound wraps causes the latter to be tightened more, and then shift axially.

It is also important that these rolls are wound tightly to prevent them from flattening out after setting of their periphery.

Therefore, the web tension with which these rolls are formed is important and often a tapering tension is used to prevent the above mentioned walk out in the roll. Tapering tension is provided by gradually reducing the tension in the Web as the roll increases in diameter. Whether a constant, tapered or other form of tension is to be applied depends on many factors, such as for example, the type of paper or board being wound and its condition.

With the foregoing in mind it will be appreciated that the ability to control and regulate the web tension under various circumstances and throughout the formation of the roll is imperative to a properly formed roll.

Accordingly, the present invention provides a web tension regulating mechanism for a hydraulic rewinder, which mechanism, in response to the diameter of the roll being formed, establishes the tension on the web in accordance with a predetermined pattern.

More specifically, the invention provides a source of power in the form of a pressure compensating, variable volume hydraulic pump, the pressure output of which determines the web tension. The pressure in the pump governor is set by a hydraulic relief valve, which valve in turn is controlled by a cam of a roll diameter sensing device. Adjustable means are provided between the cam and the relief valve so that any type or amount of tension can be quickly set for the web. In order to set any desired tension program and amount for the web, it is only necessary to set this adjustable means.

These and other objects and advantages of the present invention will appear later as this disclosure progresses, reference being had to the accompanying drawings, in which:

FIGURE 1 is a perspective view of a rewinder embodying the present invention;

CID

FIGURE 2 is an elevational, sectional view taken adjacent the cam and regulating means;

FIGURE 3 is a sectional view taken along line 3--3 in FIGURE 2;

FIGURE 4 is a view taken along line 4-4 in FIG- URE 2;

FIGURE 5 is a schematic diagram of a hydraulic circuit used with the present invention;

FIGURES 6 and 7 are sectional views through completed rolls and showing different types of web walk on FIGURE 8 is a composite chart showing how the values of the starting pressure and ending pressure for the pump are arrived at for a given set of conditions, and

FIGURE 9 is a side elevational view, on a reduced scale, of the subject rewinder.

Referring in greater detail to the drawings, the rewinder comprises a stationary stand 10 in which is rotatably mounted a turnover frame 12. Cores C and C1 are removably carried at the opposite ends of the frame 12 and the web is alternately wound around the cores. When one core has been filled to form a completed roll, the running web is spliced and started on a new roll. The completed roll is then removed and a new empty core substituted in its place for eventual filling. The above operation and construction is conventional, and if a more complete description of this general type of apparatus is required, reference may be had to the co-pending US. application Serial Number 762,646, filed September 22, 1958 entitled, Continuous Rewinder for Web Material,

which issued on January 31, 1961, as US. Patent No.

A cutting blade assembly B is mounted on a shaft 16 that in turn is journalled on the large central shaft 17 of the turnover frame. This assembly is free to swing with shaft 16 from a position closely adjacent an empty core to a position away from the core when the latter is filled. As the core is being filled, the rollers 18 of the assembly ride on the periphery of the roll and in this manner the assembly swings to follow the diameter of the roll being wrapped. This operation is fully described in the copending application, Serial No. 59,084 entitled Web Cutting Mechanism for Rewinders, filed September 28, 1960, and assigned to a common assignee with the present application, and reference may be had to that application if such is deemed necessary or desirable. It is believed sufficient to say for purposes of this disclosure, that as the build up of the roll progresses, the assembly swings outwardly, and rotates shaft 16 to which it is fixed.

The turnover frame 12 has one of the above blade assemblies for each of its ends, one for each roll, and as both ends of the frame are identical, reference will be made only to one side of the turnover frame, it being understood that the frame is symmetrical about its center shaft.

The blade assemblies B, one on each end of turnover frame 12, constitute means to sense the diameter of the roll being formed at their respective end of the frame.

Fixed to one end of shaft '16 of the assembly B, is a cam 20 which is formed from a steel plate and extends in a direction normal to shaft 16. The cam surface 20a provides a fixed rise for a follower 21 that rides thereon. As shown in FIGURE 2, the roll diameter sensing means B is at its lowermost position, that is when the core C is empty, and the cam 20 fixed with this means is of course also at the starting or initial position at this time.

A pressure regulating valve V, and a tension adjusting means A are both supported on a plate 23 fixed to and forming part of the turnover frame 12. As will more fully appear, the cam 20 actuates valve V through the adjusting means A.

The pressure regulating valve V has a shiftable actuating stem 24- and is of conventionaldesign. It acts as a relief valve in maintaining a predetermined hydraulic pressure in the pilot line PL and therefore in the governor G (FIGURE This valve may be of the type manufactured by Denison Engineering Co. and in maintaining a set pressure in the pilot line it consequently establishes the pressure in the conventional pressure compensating governor G for the fluid pump P. As shown in FIGURE 5 diagram, the governor G is located between the pilot line PL and the pump P. Thus the governor acts to control the pressure output of the pressure compensating, variable displacement pump. The pump itself is also conventional and may be of the vane type made by Racine Hydraulic Co., which will deliver whatever volume is required to maintain the pressure requirement established by its governor G, as determined by the setting of the pressure relief valve V.

As further shown in FIGURE 5, an electric motor EM drives the pump P which in turn furnishes pressure fluid to the conventional fluid motor M. Motor M is connected to the core C by means of a conventional gear train 25.

A pump 27 is located between pump P and the pilot line PL simply for furnishing pilot pressure to the pilot line PL.

In this manner the core is driven by fluid pressure furnished by hydraulic pump, and the tension of the Web being wound on the core is dependent on the pressure output of the pump. The pump pressure is regulated by the action of the governor under the influence of the relief valve. As previously mentioned, this valve in turn is actuated by the roll diameter sensing means and through the adjustment means A, new to be described.

Referring now more specifically to the adjusting means A, it comprises a slidable member 30 interposed between the cam and valve stem 24. This member has a slide 31 (FIGURE 3) secured by cap screws 32 to its underside. This slide 31 fits into the complementary track 33 formed in the fixed mounting plate 34. Member also includes a stylus 35 that is fixed to a block 36, which block is guided for sliding within the member in a direction normal to the movement of the valve stem. A threaded shaft 37 is engaged in block 36 and the knob 38 fixed to this shaft is used to rotate the latter and adjust the stylus.

The stylus 35 extends from one side of member 30 for engagement with the arm 40 that carries follower 21. Arm 40 is pivotally mounted on pin 41 carried in bracket 42 on plate 23.

In this manner the stylus is adjustable in a direction normal to valve stem movement. the stylus contacting surface 40a of the arm 40 is parallel to this direction of stylus adjustment, when the cam 20 is in the initial or starting position, as shown in FIG- URE 2.

The other side of member 30 has an adjustable stop 44 extending therefrom and threadably engaged therein. A lock nut 45 holds the stop 44 in any position to which it has been adjusted. The stop 44 engages the valve stem 24 and is used to set the initial pressure desired from the pump at the beginning of a roll. Once this initial pressure adjustment has been made in accordance with the procedure to be later described, no further adjustment of it is required.

The adjustment means A can provide a one-to-one ratio between the cam movement and the relief valve stem movement and this is the setting shown in FIGURE 2. In other words, as the cam swings and causes the arm 40 to move, the stylus is shifted the same amount as is the follower because the stylus is in alignment with follower movement. As a result, the valve stem is shifted the same amount as is travelled by the follower. Under these circumstances, a constant tension is applied to the Web throughout the roll build-up. The cam contour 20a is so designed that for every movement of the follower 21, a pressure build-up is provided that is directly proportional It should be noted that to the roll diameter build-up. This results in a constant tension as long as the one-to-one ratio is maintained between the relief valve stem movement and the cam.

The cam is so designed that it compensates for the fact that the roll build-up sensing means moves more for 1 inch roll build-up at the beginning of the roll than it does for 1 inch roll build-up toward the end of the roll. This happens because the pivot point of the sensing means and the roll center bear a different relationship to each other and to the periphery of the roll as the latter grows outwardly. Therefore, in order to make the amount of cam rise equal the amount of roll build-up at all stages of operation, the cam must compensate by having less rise during its initial movement than toward the end of its movement.

Suppose a tapering tension was desired on the web instead of the above mentioned constant tension. In that case the stylus would be adjusted to the right as viewed in FIGURE 2. Then as the cam rotated to shift the member 30 toward the valve V, the member 30 and valve stem 24 would move a lesser distance than that travelled by the follower or than the actual cam rise. Thus, the farther the stylus is moved to the right, the greater will be the decrease in web tension as the roll size increases. Even though the stylus is adjusted along the parallel surface 40a, the initial pressure setting of the pump, as established by stop 44, remains the same.

The operation of the mechanism can be illustrated by reference to the charts shown in FIGURE 8.

Chart A has as its vertical axis the force in pounds of the web pull and as the horizontal axis the web tension in pounds per inch of web width. The various web widths are plotted on this chart.

Chart B has the same vertical axis as chart A, but on the horizontal axis is plotted the torque required at the core for the various diameter rolls.

The horizontal axis for chart C is the same as that for chart B. The torque at the fluid motor constitutes its vertical axis. Various gear sets are plotted on this chart because the gears 25 may be replaced with other ratios.

Chart D is a plot of the fluid pump against its pressure range as the horizontal axis and the torque of the fluid motor.

The charts would be used as follows to find the working pressure range for the pumps for a given web tension, web width and gear ratio, and in order to provide a constant tension on the web during roll formation.

From experience the operator knows that a web tension of 12 pounds per inch of web width is desirable for the type of board to be wound. Assume further a web width of 22 inches and a core of 14 inch diameter will be used. It is also known that a finished roll diameter of 70 inches is desired, and that a gear ratio as shown by line I will be employed.

Point 50 is established on chart A for a web tension of 12 pounds/ inch and a web width of 22 inches. Projecting this point horizontally across chart B establishes points 51 and 52 on the lines of the core diameter and finished roll diameter, respectively. Reading downwardly on chart B from points 51 and 52 determines the torque required for the start and finish of the operation.

Continued projection downwardly of the points 51 and 52 on to chart C establishes points 53 and 54 on the selected gear ratio line.

Projecting points 53 and 54 horizontally to the motor characteristic line of the pump on chart D establishes points 55 and 56. Reading downwardly on chart D from points 55 and 56 then locates the pressure range of the pump. As indicated on this chart, the starting pressure of the pump would be about pounds and the pump pressure at the finishing of the roll would be about 800 pounds.

The initial pump pressure is set by adjusting the stop 44 when the cam is in the initial position. The stylus is positioned as shown in FIGURE 2 and gives a onc-to-one ratio, that is, the cam contour is of fixed rise and so designed that for every movement of the follower, the pressure build-up of the pump is directly proportional to the roll diameter build-up.

With the above settings, a constant tension on the web is provided.

As previously indicated, the surface 40a of the cam follower arm is parallel with the direction of stylus adjustment. Movement of the stylus, therefore, does not change the initial pressure setting of the pump.

If a tapering tension operation is desired, instead of the above described constant tension, the stylus would simply be moved to the right the desired amount. Under circumst-ances, the member 30 and the valve stem 24 move a lesser amount than formerly for any given movement of the cam. Therefore, while the starting tensoin is the same, by the time the roll is finished the tension has progressively decreased.

By means of the present invention an easily adjustable regulating mechanism provides for either a constant tension or various degrees of tapering tension for the web. The adjustable means provides for varying the amount of relief valve stem travel utilizing the same degree of cam travel. The rewinder is highly flexible as to its operational characteristics with a minimum of adjustment being required.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

What is claimed is:

1. A mechanism for winding a web into a roll on a core comprising, a fluid motor for rotating said core to wind said web thereon, a fluid pump connected tosaid motor for delivering fluid pressure thereto, an adjustable pressure relief valve for varying the pressure output of said pump, roll build-up sensing means including a cam that moves in response to roll build-up and adjustable means located and acting between said cam and said relief valve for varying the ratio of the amount of movement therebetween.

2. Mechanism for winding a web into a roll on a core comprising, a fluid motor for rotating said core to wind said web thereon, a fluid pump connected to said motor for delivering fluid pressure thereto, an adjustable pressure relief valve including a shiftable part for varying the pressure output of said pump, roll build-up sensing means, and adjustable means acting between said sensing means and said valve part for varying the ratio of the amount of movement therebetween, said adjustable means comprising, a slidable member engageable with said valve part, a stylus adjustable on said member, follower means movable by said sensing means and engaging said stylus to shift said member and consequently shift said part,

3. A mechanism for Winding a web into a roll on a core comprising, a fluid motor for rotating said core to wind said Web thereon, a fluid pump connected to said motor for delivering fluid pressure thereto, an adjustable pressure relief valve including a shiftable part for varying the pressure output of said pump, roll build-up sensing means including a cam that moves in response to roll build up, cam follower means for engagement by said cam and including a swingable arm, a slidable member engageable with said valve part to adjust the latter, and a stylus carried by said member for contact with said arm for movement of said member by said arm through said stylus, said stylus being adjustably shiftable on said member to vary the ratio of the amount of movement between said cam and said valve part.

4. Mechanism for winding a Web into a roll on a core comprising, a fluid motor for rotating said core to wind said web thereon, a pressure compensating variable displacement fluid pump connected to said motor for delivering fluid pressure thereto, an adjustable pressure relief valve including a shiftable part for varying the pressure output of said pump, roll build-up sensing means, a slidable member engageable With said valve part, a stylus on said member and adjustable in respect thereto, follower means movable by said sensing means and engaging said stylus to shift said member and part, said stylus being adjustable on said member to vary its point of engagement with said follower means to thereby vary the ratio of amount of movement between said sensing means and said valve part.

5. A hydraulic rewinder of the type having a frame on which a core is rotatably driven to wind a web into a roll, a fluid motor for rotating said core, a fluid pump for delivering fluid pressure to said motor, roll build-up sensing means mounted on said frame for shifting in response to roll build-up, an adjustable pressure relief valve secured on said frame for varying the pressure output of said pump and consequently the torque delivered by said core, and shiftable adjustable means mounted on said frame for engagement with said Valve, said adjustable means being shiftable by said sensing means as said roll grows in diameter to thereby adjust said valve, said adjustable means being adapted to vary the ratio of the amount of movement between said sensing means and said valve.

References Cited in the file of this patent UNITED STATES PATENTS 2,193,706 Ashland Mar. 12, 1940 2,283,321 Doe et al. May 19, 1942 2,813,601 Bourgues Nov. 19, 1957 FOREIGN PATENTS 1,049,891 France Aug. 26, 1953 

